This invention relates to a suspension and steering assembly for a snowmobile having at least one ski for supporting a front half of its body and also for steering the snowmobile.
Generally, a snowmobile includes full tractor treads supporting a rear portion of its body and also for driving the snowmobile, and one or two skis for supporting a front portion of its body and also for steering the snowmobile. When a leaf spring is used as an element of a suspension and steering assembly connecting the ski to the body of the snowmobile, it is impossible to obtain vertical displacements of a large value. Thus a coil spring and a shock absorber are mounted coaxially to provide a hollow strut member that can be expanded and compressed considerably in an axial direction relative to the ski in most of the snowmobiles now in use.
The aforesaid suspension and steering assembly is substantially similar in construction to that of motorcycles. However, unlike a motorcycle which is in contact with the ground at one point on the periphery of a tire of each wheel, a snowmobile is in contact at the undersurface of each ski with the surface of snow. The undersurface of each ski is in contact with the surface of snow in a wide area extending from front to rear, so that a high torque is required to turn the ski on the snow. When the suspension and steering assembly includes a single strut member, a torsional moment of a high magnitude would be exerted on the strut member and a high force would be exerted on the connection between assembly and the ski. This would result in an increase in cost or provide a potential source of trouble.
Also when the ski is pivotally connected to the lower end of the strut member, the ski may move about the lower end of the strut member and may not be fixed. In moving on the surface of snow which is irregular, the ski may tend to move in violent pitching motion in a vertical plane and impair the riding comfort of riders of the snowmobile. An added disadvantage is that in transporting the snowmobile it is necessary to fix the skis by using additional means which is troublesome.
The aforesaid disadvantages of the prior art are obviated by the present invention. Accordingly, the invention has as its object the provision of a suspension and steering assembly for a snowmobile which is novel and enables a torque to be transmitted smoothly to its ski when the snowmobile is steered and permits the ski to be suitably fixed during operation, so that the assembly can suitably absorb shock with respect to the pitching movement, the vertical movement and the turning movement of the ski during operation.